package day04;

/**
 * @author aiPlusPlus
 * @version 1.0
 * @date 2023/1/4 14:55
 */

/**
 * 输入一个矩阵，按照从外向里以顺时针的顺序依次打印出每一个数字。
 *
 *
 *
 * 示例 1：
 *
 * 输入：matrix = [[1,2,3],[4,5,6],[7,8,9]]
 * 输出：[1,2,3,6,9,8,7,4,5]
 * 示例 2：
 *
 * 输入：matrix = [[1,2,3,4],[5,6,7,8],[9,10,11,12]]
 * 输出：[1,2,3,4,8,12,11,10,9,5,6,7]
 */
public class Solution5 {
    public int[] spiralOrder(int[][] matrix) {
        if (matrix == null || matrix.length == 0 || matrix[0].length == 0) {
            return new int[0];
        }
        int rows = matrix.length, columns = matrix[0].length;
        boolean[][] visited = new boolean[rows][columns];
        int total = rows * columns;
        int[] order = new int[total];
        int row = 0, column = 0;
        int[][] directions = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
        int directionIndex = 0;
        for (int i = 0; i < total; i++) {
            order[i] = matrix[row][column];
            visited[row][column] = true;
            int nextRow = row + directions[directionIndex][0], nextColumn = column + directions[directionIndex][1];
            if (nextRow < 0 || nextRow >= rows || nextColumn < 0 || nextColumn >= columns || visited[nextRow][nextColumn]) {
                directionIndex = (directionIndex + 1) % 4;
            }
            row += directions[directionIndex][0];
            column += directions[directionIndex][1];
        }
        return order;

    }
}
